(NaturalNews) 229 lead smelters were shut down in the US in the 1980s and were recently evaluated in a new nationwide study. Between the 1930s and 1960s, over 600 lead smelters were in full use across the US. To extract lead, workers used blast furnaces to process ore. The byproduct that was left behind in the mines included toxic lead ores and arsenic. During a natural disaster, flood, hurricane, earthquake or tornado, these particles can be easily redistributed into the waking environment, as industrial pollutants make a haunting return.

30 percent of shuttered smelters sit in disaster-prone areas

In the new report, roughly 30 percent of the shuttered smelters lie in disaster-prone areas. These 68 old lead smelters are vulnerable. Natural disasters are capable of unearthing toxic waste from the sites, bringing large amounts back to the surface. For instance, the mile-wide tornadoes that ripped through Joplin, Missouri, three years ago also unearthed remnants of the city's industrial past, bringing lead back into neighborhood yards.

Leslie Heitkamp, Joplin's lead inspector and remediation coordinator, reported, "Trees were uprooted, houses were leveled, everything underground was now on the surface. We're still cleaning up yards every day."

In the 1800s, Joplin was a hot bed for lead mining. By 1990, the area was declared a government superfund site as officials began removing heavy amounts of lead from the environment. Even after the cleanup effort, hundreds of dormant mines and smelters were riled back to life when the tornadoes swept through three years ago.

Before the disaster, lead measurements were at an all-time low, posing no immediate threat. Now, three years after the tornado onslaught, lead contamination can be found in nearly 40 percent of Joplin's yards.

Top researcher Dr. Robert K. Kanter said, "The potential for natural disasters stirring up forgotten toxics is huge." A flood can unearth the lead and bring it to surface water. Tornadoes and hurricanes can force the lead to go airborne, depositing it in yards.

The weather's redistribution of toxins has the potential of contaminating drinking water and garden soil. Decades-old lead can enter the bodies of children who play in the dirt, lowering their IQ and altering their behavior and attention span.

The most at-risk sites are in California, where 15 old smelter sites still sit. Pennsylvania contains 14, New York has seven, Missouri six, and Illinois, five.

"If a local community knows about a former industrial site, and knows there are deposits there, that should be a focus for some planning, rather than wait for people and children to be exposed," said Dr. Kanter.

Heitkamp sees the problem as reoccurring, no matter how hard people try to clean up the lead. "Unless we tested every individual property, to about five feet below ground, I really don't think there's any way to prevent this from happening on some level again," she said.

But with enough proaction, it seems that redistribution of toxins can be thwarted in enormous ways. For example, the EPA estimates that over 100 million tons of toxic waste were removed from Joplin. Although 9 million tons of lead waste still remain in Joplin, according to estimates, the cleanup efforts prevented potential redistribution of toxins by up to 1,000 percent!

These Joplin cleanup efforts ultimately reduced elevated levels of lead at 2,600 homes in the areas closest to the old smelters. Also, before the cleanup, 14 percent of Joplin children had blood lead levels above federal health guidelines. After removing over 100 million tons or more of lead waste, the percentage of children with elevated blood lead levels dropped to 2 percent.

Cleaning up these sites, especially in the places most prone to disaster, is crucial for the long-term health of the Nation.